1. Stop at the safety boundary
Do not perform prolonged flood tests or open ceilings near electrical fixtures without professional control.
2. Capture the baseline
Take one context photo, one close view and a short note describing location, date, weather, recent water use, equipment state and occupancy.
3. Track the trigger
Shower use, spray direction and drain flow.
4. Compare, do not assume
Supports this pathway
- The stain repeats after showers
- Changing spray location changes the response
- No rain is needed
Weakens this pathway
- The mark appears during rain without shower use
- A different fixture triggers it
- The area remains dry through controlled shower tests
5. Repeat only safe checks
- Separate supply-only, drain-only and spray tests when safe
- Record start-to-stain delay
- Photograph the first wet edge below
6. Decide the next step
If the pattern is active, expanding, safety-related or requires opening inaccessible construction, stop self-help testing and prepare an evidence-based handoff. A plumber or wet-room professional should isolate supply, drain and waterproofing pathways.
7. Verify the outcome
After any action, repeat the same observation under a comparable trigger. A dry surface immediately after work is not sufficient proof when the original symptom was intermittent.
Observe→Compare triggers→Repair source→Verify outcome
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